Table 2 Bivariate associations between the independent variables and the LCQ and the SGRQ questionnaire results. (Spearman correlation coefficient (rs) or Mann-Whitney-U test)

Age (years) Rs

0.09 (p = 0.33)

0.13 (p = 0.20)

Gender: male (n = 68)

female (n = 43)

17.0 (13.4–18.6)

16.1 (12.0–19.0)

(p = 0.81)

31.1 (14.1–49.1)

31.5 (17.9–31.5)

(p = 0.79)

BMI (kg/m2) Rs

-0.28 (p = 0.004)

0.32 (p = 0.001)

Current smoking: yes (n = 13)

no (n = 98)

18.5 (13.4–19.6)

16.7 (13.1–18.5)

(p = 0.19)

23.8 (23.8–37.8)

31.5 (16.6–48.7)

(p = 0.35)

Ever smoking: yes (n = 67)

no (n = 44)

17.5 (13.4–19.0)

15.9 (12.0–18.4)

(p = 0.31)

26.6 (14.3–42.0)

33.5 (18.0–48.7)

(p = 0.30)

FVC (% predicted) Rs

0.048 (p = 0.62)

-0.20 (p = 0.051)

FEV1 (% predicted) Rs

0.09 (p = 0.33)

-0.14 (p = 0.17)

DLCO (% predicted) Rs

0.51 (P = 0.60)

-0.27 (p = 0.007)

Ground glass opacities Rs

-0.21 (p = 0.03)

0.27 (p = 0.008)

Granulomas: yes (n = 8)

no (n = 103)

12.7 (7.8–15.5)

16.9 (13.4–19.0)

(p = 0.009)

34.8 (29.8–56.7)

31.2 (14.9–43.6)

(p = 0.21)

Presence of any chronic cough comorbidities: yes (n = 26)

no (n = 85)

15.0 (12.7–18.0)

17.0 (13.4–19.0)

(p = 0.20)

34.8 (26.5–46.3)

26.8 (14.1–46.3)

(p = 0.10)

ACE inhibitor use: yes (n = 14)

no (n = 96)

16.3 (12.5–18.2)

16.8 (13.2–18.9)

(p = 0.83)

37.7 (23.9–69.1)

29.3 (15.1–43.1)

(p = 0.09)